These are early (first?) German versions of these two plays, "freely adapted by" Ferdinand Bonn, issued as Nos. 4839 and 4888 of Philipp Reclam's "Universal Bibliothek" of dramatic works; we do not know for certain just when these two volumes were published, as the only date to appear within is each play's first-production date in Berlin -- 2 July 1906 and 17 January 1907 respectively.~The English-language play "Sherlock Holmes" in four acts has an interesting history. During the years after Doyle killed off Holmes at Reichenbach Falls in 1894, he fell short of cash but was determined not to resurrect Holmes. He tried his hand at turning elements of some Holmes cases into a play -- but his agent A.P. Watt could see that it needed much work, and conferred with impresario Charles Frohmann, who traveled to London to ask Doyle if the American playwright/actor William Gillette could substantially adapt the play -- to which Doyle agreed. Gillette's play (he also starred in it) premiered in Buffalo on October 23, 1899, the first of about 1300 worldwide performances. (It was Gillette who put the curve in Holmes's pipe -- so that he could better deliver his lines, and/or so that his face would not be obscured.)~"Der Hund von Baskerville" is also noteworthy, in that its subtitle (translated) reads "Freely Adapted from the Stories of Poe and Doyle." In 1914, Richard Oswald with Union-Vitascope Studios in Berlin created, from this German play, the first film adaptation (silent) of Doyle's novel, anywhere.~Condition is near-fine, with minor edge-wear (the former's front cover has a chip alongside the spine, a faint ink-stamp, and an early signature). Item #13904